Abstract This paper studies the modulation strategy and neutral point voltage control method of N-phase neutral point clamped 3-level inverter. A novel PWM strategy for N-phase NPC 3LI is proposed, named N-phase virtual space vector pulse width modulation strategy. This PWM strategy unconditionally balances the midpoint voltage by accurately calculating and executing a 1-level duty cycle per phase. Some non-ideal factors, such as dead zone insertion, will destroy the midpoint voltage self-balancing capability of the PWM strategy. Therefore, this paper also proposes active neutral point voltage control based on N-VSVPWM. Theoretical analysis and experimental results show that N-VSVPWM has better midpoint voltage control capability and better harmonic characteristics than space vector pulse width modulation strategy, but the switching loss increases.
Jiang Weidong,Li Jinsong,Wang JinPing等. A PWM Strategy for Neutral Point Clamped N-Phase 3-Level Inverter[J]. Transactions of China Electrotechnical Society, 2019, 34(10): 2194-2206.
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2019, Vol. 34 
